This article presents the results of a Dutch national study into performance of mechanical ventilation systems and its effect on the self-reported health and perceived indoor environmental quality of occupants. Ventilation systems with natural supply and mechanical exhaust ventilation (MEV) and balanced mechanical supply and exhaust systems with heat recovery (MVHR) were investigated. Surveys were performed in 299 homes, which included visual inspections and measurements of ventilation rates per room and installation noise levels. An additional survey regarding perceived indoor air quality and self-reported health was completed per household. Results show that shortcomings are common in many homes and for both MVHR and MEV. Shortcomings include insufficient ventilation rates, high noise levels, unclean systems and insufficient maintenance. The causes have been found to be related to failures during all the different stages of the building process, from design to use. The indoor environmental quality was perceived more positive in homes with MEV when considering air quality, perceived dryness of air, noise and control options. There was no clear relationship between self-reported health and shortcomings of ventilation systems. Some practical implications are presented to avoid shortcomings in future dwellings.@en

Buildings located close to busy roads, industry or stock farms, are of risk of increased indoor particle concentrations, which negatively impacts the health of the building occupants. In order to reduce the exposure of the building occupants, it is important to take measures to reduce the concentration of particulate matter indoors. Solutions for existing buildings include application of improved filters in the air handling units, using local air cleaners and limit the use of operable windows. However, little is known about the overall effectiveness of these measures in existing buildings that are in use. The aim of our study was to quantify the effectiveness of particle reducing measures in buildings at high traffic locations. We performed a field study in a school in a neighbourhood between highways. In this school the effect of improved filters in the air handling unit, a HEPA filter at room level as well as the combination of both interventions on the particle concentrations indoors were studied. We quantified the effect of the interventions by momentary measurements of PM2,5 and ultrafine particles (≥4 nm). Moreover, PM2.5 was continuously measured outdoors and indoors. The ePM1 85% filters in the AHU seemed effective on the reduction of (ultrafine) particles (nearly 75% reduction of PM2,5). The use of a HEPA filter was not effective in our test situation.@en

The past years valuable data on indoor environments in Dutch schools has been collected by the ABCD tool (an online tool available for Dutch primary schools to check the indoor environmental quality (IEQ) of their building). In this paper we analyse the data on perceived IEQ. Data collected from 97 primary schools was available for analysis. We can conclude that the perceived IEQ in Dutch school is very poor on indoor air quality ('stuffy air', 'dust or dirt' and 'dry air') and thermal comfort ('high temperatures in summer'). The results of the questionnaire have been used to update the reference file for the ABCD tool.@en

In this paper we describe the ABCD tool, an online tool in which schools can measure their perceived indoor environmental quality and energy consumption compared to a reference file for a 'reasonably good Dutch primary school'. Additionally, by giving some basic building characteristics the school obtains an overview of standard measures that could be used to improve their indoor environment.@en

The quality of mechanical ventilation systems (mechanical air supply and exhaust and natural air supply and mechanical exhaust) was studied in 299 recently built single-family houses. The quality of ventilation systems was determined by measurements as well as technical inspections for the aspects indoor air quality, thermal comfort and noise. The performance was generally poor for both types of ventilation systems. Common shortcomings regarding indoor air quality are insufficient air supply and exhaust rates, improper construction of ductwork, insufficient control options and poor maintenance. Common failings regarding thermal comfort are overheating if no 'bypass' section is installed as well as draught under air supply valves. Common shortcomings regarding noise are the position of the ventilation unit, the absence of properly installed silencers, and improper construction of ductwork. The overall poor performance seemed to originate from flaws in design, construction, maintenance as well as the use of the ventilation systems.@en